Synergistic Effects of Traumatic Head Injury and Apolipoprotein-epsilon4 in Patients With Alzheimer's Disease

TLDR

The APOE ε4 allele increases Alzheimer’s disease risk, and beta‑amyloid deposition from age, genetics, or head injury may also contribute to its pathogenesis. This study investigated whether traumatic head injury and APOE ε4 together elevate AD risk in 236 community‑dwelling elderly persons. The authors evaluated AD risk by assessing the presence of traumatic head injury and APOE ε4 genotype in a cohort of 236 elders. Combined APOE ε4 and head injury raised AD risk tenfold compared with a twofold increase from APOE ε4 alone, whereas head injury alone did not increase risk, demonstrating a synergistic relationship. NEUROLOGY 1995;45:555‑557.

Abstract

Article abstract-The apolipoprotein-epsilon4 allele increases the risk of Alzheimer9s disease (AD), but cerebral deposition of beta-amyloid with age, a genetic mutation, or head injury may contribute to the pathogenesis of this disease. We examined the risks of AD associated with traumatic head injury and apolipoprotein-epsilon4 in 236 community-dwelling elderly persons. A 10-fold increase in the risk of AD was associated with both apolipoprotein-epsilon4 and a history of traumatic head injury, compared with a two-fold increase in risk with apolipoprotein-epsilon4 alone. Head injury in the absence of an apolipoprotein-epsilon4 allele did not increase risk. These data imply that the biological effects of head injury may increase the risk of AD, but only through a synergistic relationship with apolipoprotein-epsilon4. <b>NEUROLOGY 1995;45: </b> 555-557